[Belac]

On the 'using castle turns to recruit Shuten-Doji' question, there should be ample time to recruit them instead of Bakemono Sorcerers: When you haven't yet built a lab in the fort, and when you don't have enough money (because you have lots of forts and are recruiting Bakemono Sorcerers from several).

So somewhere in your empire, at some point, there should always be a place where you can recruit non-mage commanders.